1,987 research outputs found
decays to from new data on
Data on the reaction with ,
taken with unpolarized or polarized beams in combination with an unpolarized or
polarized proton-target, were analyzed within the Bonn-Gatchina (BnGa) partial
wave analysis. Differential cross sections, several spin density matrix
elements, the beam asymmetry , the normalized helicity difference ,
and the correlation between linear photon and longitudinal target
polarization were included in a large data base on pion and photo-induced
reactions. The data on photoproduction are used to determine twelve
branching ratios; most of these are determined for the first
time.Comment: 6 pages, 4 figures, 2 table
Ultrafast relaxation dynamics of optically excited electrons in Ni3-
Photon-induced ultrafast energy dissipation in small isolated Ni-3(-) has been studied by two-color pump-probe photoelectron spectroscopy. The time-resolved photoelectron spectra clearly trace the path from a single-electron excitation to a thermalized cluster via both inelastic electron-electron scattering and electron-vibrational coupling. The relatively short electron-electron-scattering time of 215 fs results from the narrow energy spread of the partially filled d levels in this transition-metal cluster. The relaxation dynamics is discussed in view of the cluster size and in comparison to the totally different relaxation behavior of s/p-metal clusters
About the strength of correlation effects in the electronic structure of iron
The strength of electronic correlation effects in the spin-dependent
electronic structure of ferromagnetic bcc Fe(110) has been investigated by
means of spin and angle-resolved photoemission spectroscopy. The experimental
results are compared to theoretical calculations within the three-body
scattering approximation and within the dynamical mean-field theory, together
with one-step model calculations of the photoemission process. This comparison
indicates that the present state of the art many-body calculations, although
improving the description of correlation effects in Fe, give too small mass
renormalizations and scattering rates thus demanding more refined many-body
theories including non-local fluctuations.Comment: 4 pages, 4 figure
The Role of the PAX8/PPARĪ³ Fusion Oncogene in Thyroid Cancer
Thyroid cancer is uncommon and exhibits relatively low mortality rates. However, a subset of patients experience inexorable growth, metastatic spread, and mortality. Unfortunately, for these patients, there have been few significant advances in treatment during the last 50 years. While substantial advances have been made in recent years about the molecular genetic events underlying papillary thyroid cancer, the more aggressive follicular thyroid cancer remains poorly understood. The recent discovery of the PAX8/PPARĪ³ translocation in follicular thyroid carcinoma has promoted progress in the role of PPARĪ³ as a tumor suppressor and potential therapeutic target. The PAX8/PPARĪ³ fusion gene appears to be an oncogene. It is most often expressed in follicular carcinomas and exerts a dominant-negative effect on wild-type PPARĪ³, and stimulates transcription of PAX8-responsive promoters. PPARĪ³ agonists have shown promising results in vitro, although very few studies have been conducted to assess the clinical impact of these agents
The formation of Uranus and Neptune among Jupiter and Saturn
The outer giant planets, Uranus and Neptune, pose a challenge to theories of
planet formation. They exist in a region of the Solar System where long
dynamical timescales and a low primordial density of material would have
conspired to make the formation of such large bodies ( 15 and 17 times as
massive as the Earth, respectively) very difficult. Previously, we proposed a
model which addresses this problem: Instead of forming in the trans-Saturnian
region, Uranus and Neptune underwent most of their growth among proto-Jupiter
and -Saturn, were scattered outward when Jupiter acquired its massive gas
envelope, and subsequently evolved toward their present orbits. We present the
results of additional numerical simulations, which further demonstrate that the
model readily produces analogues to our Solar System for a wide range of
initial conditions. We also find that this mechanism may partly account for the
high orbital inclinations observed in the Kuiper belt.Comment: Submitted to AJ; 38 pages, 16 figure
Fast Neutron And Gamma-ray Detectors For The Csiro Air Cargo Scanner
oS(FNDA2006)074 Ā© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Q value and half-life of double-electron capture in Os-184
Os-184 has been excluded as a promising candidate for the search of
neutrinoless double-electron capture. High-precision mass measurements with the
Penning-trap mass spectrometer TRIGA-TRAP resulted in a marginal resonant
enhancement with = -8.89(58) keV excess energy to the 1322.152(22) keV 0+
excited state in W-184. State-of-the-art energy density functional calculations
are applied for the evaluation of the nuclear matrix elements to the excited
states predicting a strong suppression due to the large deformation of mother
and daughter states. The half-life of the transition in Os-184 exceeds T_{1/2}
> 1.3 10^{29} years for an effective neutrino mass of 1 eV.Comment: accepted in Phys. Rev.
Bis[(1-ammonioĀethane-1,1-diĀyl)diphosphoĀnato-Īŗ2 O,Oā²]diaquaĀnickel(II) nonaĀhydrate
The title compound, [Ni(C2H8NO6P2)2(H2O)2]Ā·9H2O, exhibits a slightly distorted octaĀhedral coordination environment around the NiII atom. It contains two molĀecules of 1-aminoĀĀethylĀidenediphosphoĀnic acid in the zwitterionic form, coordĀinated via O atoms from two phosphoĀnate groups and creating two six-membered chelate rings. Two water molĀecules in cis positions complete the coordination environment of the NiII atom. The title compound contains nine partly disordered solvent water molĀecules, which create a three-dimensional network of strong OāHāÆO and NāHāÆO hydrogen bonds
Tuft dendrites of pyramidal neurons operate as feedback-modulated functional subunits
Dendrites of pyramidal cells exhibit complex morphologies and contain a variety of ionic conductances, which generate non-trivial integrative properties. Basal and proximal apical dendrites have been shown to function as independent computational subunits within a two-layer feedforward processing scheme. The outputs of the subunits are linearly summed and passed through a final non-linearity. It is an open question whether this mathematical abstraction can be applied to apical tuft dendrites as well. Using a detailed compartmental model of CA1 pyramidal neurons and a novel theoretical framework based on iso-response methods, we first show that somatic sub-threshold responses to brief synaptic inputs cannot be described by a two-layer feedforward model. Then, we relax the core assumption of subunit independence and introduce non-linear feedback from the output layer to the subunit inputs. We find that additive feedback alone explains the somatic responses to synaptic inputs to most of the branches in the apical tuft. Individual dendritic branches bidirectionally modulate the thresholds of their input-output curves without significantly changing the gains. In contrast to these findings for precisely timed inputs, we show that neuronal computations based on firing rates can be accurately described by purely feedforward two-layer models. Our findings support the view that dendrites of pyramidal neurons possess non-linear analog processing capabilities that critically depend on the location of synaptic inputs. The iso-response framework proposed in this computational study is highly efficient and could be directly applied to biological neurons
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